Do you have your grandparents births, deaths or marriage? They should show the mother's name.
I've had a quick look on ScotlandsPeople for a death.
2 George Cathcarts that were born around the time you're looking for.
George Cathcart died in Springburn 1923 aged 68 GROS 644/06 0271
George Johnston Cathcart died Tradeston 1938 age 84 GROS 644/16 0108
If you can find the correct death record, it will also tell you his wifes name and would make a search of the census records easier. Census records will confirm whether or not he was born in Ireland.
Do you know when he came to Scotland?
A printfield labourer is in the textile industry.